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| SuperGIS Mobile Engine Development Application Yeh-Liu Mobile Guide System |
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The development of wireless transmission technology and the rise of the mobile devices have broken the limitation on portability of Geographic Information System and even expanded its application levels. So the Mobile GIS has drawn more and more attention from the GIS field in the recent years. Mobile GIS like an extension of Web-GIS but its GIS foundation is unchanged: moreover it allows acquiring, storing, integrating, processing, analyzing and presenting of spatial data just like what Web-GIS can do (Ren Fu, 2002). With the additional significant feature of transferability compared to Web-GIS, Mobile GIS is able to be applied in all fields, such as in personal navigation, E-commerce application, spatial data field surveying system, emergency response and rescue system and more.
Moreover, as the domestic economic progresses and the two-day weekend is implemented, the recreational and leisure activities have turned to be the periodical activities for people. Prior to the popular use of hand-held electronic information devices, paper maps, travel guide books or newspapers were a brought for people with a desire to get more precise information on restaurants, transportations, accommodations and scenic spots when traveling. But it was a shame that the information on paper maps and guide books was often updated at very long intervals, inconvenient to be brought with or quite uneasy for the user to make a travel summary. Fortunately, lately with the wide spreading of electronic information and popular use of hand-held devices, a number of recreational attraction centers are offering electronic information via low-cost electronic transmission, such as E-mail, exclusive web, major web portals or some electronic forums to appeal to the visitors. However, in terms of facts, those attraction centers who are offering related electronic information for the public, are not the majority. Even if the attraction centers can offer electronic information, it is often the case that the tourists cannot find the correct location of the attraction or that the scenic attraction centers are incapable of providing sufficient travel guides. In such circumstances, the hand-held electronic information device can be a fine and effective solution to solve the problems mentioned. For these reasons, the Mobile GIS applications in travel and tourism industries enjoy splendid progresses and results. |
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| The origin of Yeh-Liu mobile guide system |
| Yeh-Liu Geopark is one of the most internationally-known scenic spots in northern Taiwan and a must-visit for international tourists who are visiting Taiwan. So in recent years, a huge budget has been provided to the park for an advancement of hardware equipments, anticipating to give the domestic and foreign tourists a wonderful experience. Furthermore, in order to allow the visitors to know more about the unique natural sceneries in the park, the tourist center is offering multi-media briefings, narrators, and folders for their references. Nevertheless, with 50,000 visitors each month, except for those who take the folders themselves, only 27% of the visitors receive narration information. Therefore, the park is planning to develop a set of GPS-navigation-integrated electronic guide system so that the visitors are able to receive the abundant narration information. Hereafter, the visitors can enjoy the guide himself on hand-held devices with electronic guide system installed. Since the traditional paper contexts and figure descriptions are imported into the electronic guide system, visitors can easily use the electronic guide service, which is simply like the guide services that are usually seen. And through the integration of GPS and GIS, the damage on scenery caused by setting description boards can therefore be prevented. |
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| SuperGIS Mobile Engine briefing |
| This GPS-navigation-integrated electronic guide system is developed using SuperGIS Mobile Engine, the latest development component released by SuperGeo Technologies in 2008. SuperGIS Mobile Engine is designed as a SDK (Software Development Kit) for program designers and system developers to perform second-time development. Constructed on .NET Compact Framework, it can quickly create various GIS application programs and is able to run on all .NET CF supportive platforms, including desktop PC and intelligent devices. In the process of the developing, all the built-in .NET CF component libraries are able to be used, and so are the hundreds of components and controls provided by SuperGIS Mobile Engine, so that the developers different demands can be fully satisfied. |
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| SuperGIS Mobile Engine Application Development |
| Next, we are addressing how to use SuperGIS Mobile Engine to develop the guide system, and through the various objects that SuperGIS Mobile Engine provides, most of the required functions for the guide system can be therefore implemented and supported in a very short time. |
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Map display |
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SuperGIS Mobile Engine displays maps on the screen by using MapCtrl, and Layers property records all the layers added. The loading of feature and raster layers in various formats is supported by the system. Users can also customize the feature symbol for each added feature layers. The layers can be added by modifying the codes directly or by loading the layer setting files, which is generated by SuperWebGIS Mapper on the desktop computer, to SuperGIS Mobile Engine of the intelligent device. Different devices may have different file paths, so if necessary, the configuration file path may have to be modified by hand. For example, the first letter of an absolute file path of a desktop device must be an English letter, such as 'C' or 'D'; however, of an intelligent device, the file path usually starts with '\' more often. |
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GPS device connection |
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GPS is the very crucial in the development of Mobile GIS, so SuperGIS Mobile Engine also provides various objects to support the receiving and processing of GPS signals. Three major interfaces are offered: IGpsConnection, IGpsParser and IGpsDisplay. IGpsConnection mainly connects GPS data source for data reading; IGpsParser analyzes GPS data stream in the appointed format and acquires the latitude and longitude or other attribute data; IGpsDisplay can provide a graphic interface and display the receiving of satellite signals.
When developing GPS applications, the first step is to connect to GPS devices. erialPortGpsConnection inherits from IGpsConnection and System.IO.Ports.SerialPort, supporting the connection of various serial port resources, such as Bluetooth, CF card, infrared or the built-in GPS hardware of smart devices. It provides the properties required for managing GPS devices, including PortName, BaudRate, StopBits and DataBits. Through the DetectGPS and CheckComPort methods, we can detect and check whether the defined port is actually a GPS device. The ShowPreferencesDialog method is used to show the property settings page, which allows users to configure the PortName, BaudRate and other properties.
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| The management interface of the guide system |
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After connecting to the GPS device, the received GPS data must be analyzed according to a specific format, converting it to usable information. NmeaGpsParser supports the analysis of GPS signals in NMEA 0183 forma. After obtaining the related GPS data, it will be saved as the GpsArgs property. GpsArgs is a class used to record data related to the GPS. When usable latitude and longitude data is received, the OnPosition event will be triggered; when new satellite data is received, the OnSatellites event will be triggered; when GPS data flow is received, the OnSentence event will be triggered. Therefore, if you use SuperGIS Mobile Engine to develop a guidance system, the guidance system will utilize the OnPosition event to trigger and show various kinds of guidance information to the user. For instance, the current coordinate position can be used to search for nearby scenic spots and display the direction to the next scenic spot. |
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| The built-in property page of the NmeaGpsParser |
The GPSStatusButton provides the interface for displayinf the GPS signal. |
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| In addition to the current GPS position information, if the users trail and direction can also be increased to the map, it will be more helpful for the user to realize where he is and to be more precisely guided towards the correct direction. As long as the MapCtrl and GpsParser properties of the MapGpsDisplay object, which is provided by SueprGIS Mobile Engine, are set, the trail, current position and heading direction can be automatically labeled on the map control. |
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| Using the MapGpsDisplay on pictures to display the GPS trail and heading direction. |
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Spatial relation |
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The scenic spot information, itinerary and danger zones used in the guide system are all recorded in feature layers. For example, the scenic spot information is recorded in a point layer, in which each point feature represents one scenic spot, while itinerary and danger zones are recorded as line features. If the distance from the current coordinates to any line feature that represents the danger zone is smaller than the set value, it means that you are approaching the danger zone, so the system would show warning messages or play sound effects for warning. All functions mentioned above are acquired by the spatial calculation and relationship of various geometries. The ISpatialOperator interface of SuperGIS Mobile Engine supports spatial calculation of various types of geometries, for example, through the Distance method to acquire the distance between two geometries; furthermore, the geometries spatial relation can be obtained through the many methods provided by the ISpatialRelation. |
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| The guide system is implemented through spatial relation and operation.. |
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| Conclusion |
| The demand for electronic guide system is getting higher and higher as the Mobile GIS technologies advances day by day. With SuperGIS Mobile Engines strong developing strengths, developers demands on the exclusive guide systems for different scenic spots can be satisfied. No doubt, SuperGIS Mobile Engine is not only limited to the development of guide systems. Its hundreds of components and controls will allow the development of other Mobile GIS systems, such as personal navigation, E-commerce application, spatial data field survey system, emergency response and rescue system and more, to be done. The applications developed by SuperGIS Mobile Engine is rather diversed. |
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